要 旨 ：
The highest achievable superconducting critical temperature (Tc) in intermetallic iron-pnictide superconductors (specifically, the
122 family) was heald to be 39K when K is substituted for Ba in BaFe2As2. Our group was among the first to report traces of
superconductivity in the 40-50K range when rare earth elements are doped for Ca in CaFe2As2. Unfortunately, these materials display
a drastically low shielding volume fraction and correspondingly low critical current densities. Recent studies aimed at increasing
this volume fraction, including high pressure synthesis and unusual doping schemes, have met with varying levels of success. This
talk will detail these efforts and the outlook for bulk superconductivity in this system.